This invention relates to an animal separating or sorting gate which may be operated with a minimum of people, which allows the operator to vary the sizes of animals being separated from one another and which is quickly adjusted and operated.
A farmer or rancher frequently desires to separate different sizes of animals from one another, such as calves from their mothers or hogs of a certain weight from hogs of another weight for marketing. In the past, some farmers have manually separated such animals by sorting through the herd and weighing the animals which appeared to be of proper size before removing them.
Another approach has been to arrange an adjustable gate between two pens or stockades. The animals to be separated are located in one pen and an incentive such as food is located in the other. The gate is operated allowing either large animals or small animals to pass through the gate to reach the food.
One such approach, forming an opening in such a gate which will allow small animals to pass but which stops large animals, by using sliding members in the gate is disclosed in U.S. Pat. No. 2,803,074, issued Aug. 20, 1957, to Brokish ("Brokish"), U.S. Pat. No. 2,972,825, issued Feb. 28, 1961 to Stillwell, et al. ("Stillwell, et al."), U.S. Pat. No. 3,072,100, issued Jan. 8, 1963, to Dustin ("Dustin"), and U.S. Pat. No. 3,861,359, issued Jan. 21, 1975, to Pals ("Pals"). Brokish discloses a gate with a door having an opening through which small animals may pass. A sliding structure adjustably closes off the opening to allow varying sizes of animals to pass through the gate. Although the Brokish gate may be easily operated by one person, the opening appears to allow only one or a limited number of animals to pass through the gate at one time so that the sorting process may be lengthy. The Stillwell, et al., gate also has an opening adjustably covered by a sliding structure and also appears to allow only a limited number of animals to pass through the gate at one time.
The Dustin gate has more than one opening covered by sliding structures, and thus would appear to allow completion of the animal separating process in a shorter period of time than the Brokish and Stillwell, et al., gates. The sliding structures of the Dustin gate, however, are operated by a crank mechanism which may take longer to operate than a sliding structure held in place by pins such as in Brokish. Further, because the sliding structures cannot be moved quickly with the crank mechanism, animals may become stuck and possibly injured in the gate as the sliding structures are being opened or closed and the animals attempt to force their way through the openings.
The Pals gate has a single opening adjustably covered by a sliding structure, and that structure is also controlled by a crank mechanism as in the Dustin gate. However, Pals also discloses a vertically swinging rectangular door that swings from the top of the opening and partially covers it. The door swings in the direction in which the animals pass so that they may push the door out of the way when they pass through the gate to the food or other incentive, but cannot push the door in the other direction if they attempt to pass back through the gate. Thus, although the animal sorting process may be a lengthy one with a Pals gate because it has only one opening, that gate does include a means for separating animals both by height and weight simultaneously.
A second general approach to the use of gates to separate animals by size is to include one or more doors for covering the opening through which the smaller or larger animals may pass, rather than sliding members. U.S. Pat. No. 995,338, issued June 13, 1911, to Folsom ("Folsom"), for instance, discloses a gate having a door with an upper part and a lower part, either part being independently swingable. The lower part may be swung open to let small animals pass through the gate, and the upper part may be swung open with the lower part closed to allow larger animals, which can step over the closed lower part, to pass through the gate. The upper part is also slidably vertically adjustable so that an opening can be formed between the upper and lower parts to allow animals to pass through the gate which can step over the lower part while simultaneously ducking the raised upper part. U.S. Pat. No. 2,144,896, issued Jan. 24, 1939, to Raymond ("Raymond") also discloses a gate with a door having an upper part and a lower part. In the Raymond gate, however, the lower part swings vertically about its upper horizontal edge.
The Folsom and Raymond gates both allow larger numbers of animals simultaneously to pass through their openings than the gates mentioned above. However, they may require extra manpower to close the swinging portions when it is desired to halt the separating process. This difficulty occurs because when the animals perceive the swinging members being closed, they will head for the remaining gap left open and thus bunch up at that end of the swinging portion and apply pressure against it, making the gate difficult to close.